ATtiny20 is a microcontroller in the Atmel AVR family. It is available in the 12-pin WLCSP, 14-pin SOIC, 15-pin UFBGA, or 20-pin VQFN package with a 4, 8, or 12 MHz selectable clock speed. Runnning at higher clock speeds require higher minimum operating voltages, with 2.7 volts for 8 MHz and 4.5 volts for 12 MHz. It has the following features: